Arctic P14 PWM PST CO in detail
Longer life in exchange for more noise? These are also some of the agenda items we’ll cover in our comparison of the Arctic P14 CO fan with the fluid bearing variant (P14). These are actually the main points. In any case, the ball bearings in the more expensive variant of these fans also have specific features that can be easily observed and distinguished even in normal, “home” use.
The popular Arctic P14 fan is also sold in “CO” models. Compared to the basic models without this designation, these have ball bearings (instead of fluid bearings). More precisely double, or double-row, ball bearings. Their advantage lies primarily in their longer service life, although the idea of what exactly is meant by this is rather vague.
Arctic doesn’t get too specific about the numbers in this case either. However, the marketing description states that the double ball bearing is designed for continuous operation (hence the “CO” designation) 24/7. Polluted surroundings and high temperatures are expected to have less impact on service life. However, this presentation from Arctic doesn’t have to go against the fluid bearing variant, but it can as well. Arctic’s wording here probably refers mainly to the comparison with plain bearings and with “other” ball bearings (rather than with the cheaper FDB variant of the P14). Arctic is asking for more money for this too. At the same time, there is an honest manufacturer’s note on the higher noise level of these bearings. By just how much, we’ll discuss in detail.
Before analyzing and evaluating the fans themselves, it is a good idea to focus on the sub-details. These are geometrically indistinguishable from the cheaper variant (P14).
The impeller is made up of five equally long, thick and curved blades. And you already know from the P14 PWM PST tests that in terms of airflow to noise ratio, this is a pretty good way to go. That is, if we are talking about this low price range, within which you have to accept certain acoustic compromises. These are noisier low frequencies due to the nature of the vibrations on the relatively flexible PBT blades. Aside from that, however, this is a geometrically very efficient fan even in situations where the fan operates on obstacles.
In addition to the high airflow, it also achieves high static pressure, which is supported by the slightly thicker profile (27 mm) than normal (25 mm). However, it is still a low-cost manufacturing design without any extras. You won’t even find the typical anti-vibration pads in the corners of the fan, but those would be rather unnecessary anyway. At the very least, as far as a new, unused fan is concerned, the vibrations measurable on the frame are negligible, and unless you come across some outright bad piece, they won’t be a source of secondary noise by vibrating the material the fan is in contact with.
One thing in the corners of the fan is worth paying attention to. These are some kind of “ribs” perpendicular to the cross-section, which could provide reinforcement for the frame. This can come in handy for example when tightening with more torque force, after which there is still no deformation of the frame. In practice, this is nothing major – considering the rather large gap between the frame tunnel and the blade tips (about 2 mm) – but it is a feature that costs nothing extra and can be useful in critical situations. We don’t know that though, and we don’t know at all if Arctic’s implementation of it is not aimed at something quite different than increasing the strength of the frame. In the end, it even looks rather “nice”, but the visual side of things is for everyone to judge for themselves.
The tested fan is in revision 3, which is still the latest revision for the P14 PWM PST fan at the time of testing. The “PWM” in the designation of this particular model (with P/N ACFAN00126A) refers to pulse modulation support with connection via a 4-pin connector. “PST” then stands for “power sharing technology” with the ability to connect fans in series. The secondary connector (female) is used for this.
For more design details on the P14 PWM PST CO fan, you can also check out the P14 PWM materials. They share the vast majority of features and we haven’t mentioned all of them again with this fan (don’t let us bore you from article to article).
And one more thing: To navigate through the result graphs as easily as possible, you can sort the bars according to different criteria (via the button on the bottom left). By (non)presence of lighting, profile thickness, brand, bearings, price or value (with the option to change the sorting to descending or ascending). In the default settings, there is a preset “format” criterion that separates 120mm fans from 140mm fans.
- Contents
- Arctic P14 PWM PST CO in detail
- Overview of manufacturer specifications
- Basis of the methodology, the wind tunnel
- Mounting and vibration measurement
- Initial warm-up and speed recording
- Base 6 equal noise levels…
- ... and sound color (frequency characteristic)
- Measurement of static pressure…
- … and of airflow
- Everything changes with obstacles
- How we measure power draw and motor power
- Measuring the intensity (and power draw) of lighting
- Results: Speed
- Results: Airlow w/o obstacles
- Results: Airflow through a nylon filter
- Results: Airflow through a plastic filter
- Results: Airflow through a hexagonal grille
- Results: Airflow through a thinner radiator
- Results: Airflow through a thicker radiator
- Results: Static pressure w/o obstacles
- Results: Static pressure through a nylon filter
- Results: Static pressure through a plastic filter
- Results: Static pressure through a hexagonal grille
- Results: Static pressure through a thinner radiator
- Results: Static pressure through a thicker radiator
- Results: Static pressure, efficiency depending on orientation
- Reality vs. specifications
- Results: Frequency response of sound w/o obstacles
- Results: Frequency response of sound with a dust filter
- Results: Frequency response of sound with a hexagonal grille
- Results: Frequency response of sound with a radiator
- Results: Vibration, in total (3D vector length)
- Results: Vibration, X-axis
- Results: Vibration, Y-axis
- Results: Vibration, Z-axis
- Results: Power draw (and motor power)
- Results: Cooling performance per watt, airflow
- Results: Cooling performance per watt, static pressure
- Airflow per euro
- Static pressure per euro
- Results: Lighting – LED luminance and power draw
- Results: LED to motor power draw ratio
- Evaluation
Expected results, but still an interesting showcase of the effect of only changing the bearings.
So, the “hum” is still here all the same, despite some claims that the CO version fixes it. ThermalLeft has documented sound differences between revisions too (https://www.youtube.com/watch?v=nt8Ao4GDmzY), but even Arctic themselves doesn’t think revisions will have such an effect. I am starting to think it’s possibly a batch “issue” that may have introduced different properties to the rotor material.
I guess those claims of the CO rumbling less will never come from an official source (from Arctic)? They don’t seem to list among the changes across the revisions the modifications that address this. And personally, I don’t even see the technical reason behind the CO variant or the higher P14 revision (2 vs. 4) being quieter on lower frequencies. The impeller seems to have the same parameters in terms of geometry or material used. Nevertheless, there can certainly be a situation where different noise levels are measured across different fans. But it may not be due to different revisions, and perhaps it may be possible to observe this across different fan pieces of the same revision due to different manufacturing tolerances (which are high in the low-end after all)?
An analysis that tracks the tonal peaks of multiple pieces from the same revisions on each side would shed more light on this. From our experience, we note that the shape of the spectrograms of multiple pieces of the P14 PWM PST rev. 4 compared to P14 PWM PST CO rev. 3 in the low frequency band is identical at the same speed. The small differences in the spectrograms that you see in the tests are mainly just due to the fact that in modes normalized by the same noise levels, the speeds of the two variants (P14 and P14 CO fans) are slightly different. For the CO, the speeds are always set a little lower due to the noisier bearings.
Perhaps what is known as “resonance” is something else that’s not the frequency spike at ~100 Hz. Namely, the sudden increase in noise at specific RPM ranges. Or, perhaps the two issues are lumped together when people talk about it, when in fact the two (sound profile with pronounced low frequency peak, and some RPM ranges being suddenly louder) are different issues (that perhaps are related).
I am sure you would have noticed and mentioned it though, when you’re testing the fans and adjusting the fan speeds again and again.